介质覆盖金属光栅的光学特性研究

发布时间：2018-06-07 10:04

本文选题：耦合模理论 + 时域有限差分法　；参考：《长春理工大学》2017年硕士论文

【摘要】：表面等离子激元是电磁场与金属表面传导电子相互耦合所产生的传导电子集体共振的结果。表面等离子导模与表面等离子共振导模这两类模式都是由金属-介质界面支撑。表面等离子导模在金属-介质界面传播与外界电磁场不存在耦合,即没有辐射损耗;表面等离子共振导模的电磁场也是被限制在金属-介质界面传播,它能够利用光栅、棱镜、近场来激发,不同于表面等离子导模,表面等离子共振导模能够与外界电磁场进行强烈的相互耦合。利用金属光栅结构激发表面等离子导模与表面等离子共振导模得到了广泛研究。采用时域有限差分法与耦合模理论,本文研究了介质覆盖金属光栅表面等离子混合模式的光学共振特性。研究结果表明,在所研究的结构中,覆盖介质支撑的混合表面模式与金属光栅所支撑的表面等离子模式相互作用引起抗交叉效应;利用耦合模理论,还对此系统的反射特性进行了建模研究,得出了减小吸收的条件。此耦合系统的所有光学特性都采用了时域有限差分法进行验证,理论结果与数值模拟结果一致。这个研究可以应用在传感器上,在金属光栅上覆盖上一层介质能够防止其被氧化,极大地提高了传感器的性能与寿命。
[Abstract]:Surface plasmon is the result of collective resonance of conducting electrons produced by the interaction of electromagnetic field and conducting electrons on metal surface. Both surface plasmon modes and surface plasmon resonance modes are supported by the metal-dielectric interface. There is no coupling between the surface plasma conduction mode and the external electromagnetic field, that is, there is no radiation loss, and the electromagnetic field of the surface plasma resonance conduction mode is also confined to the metal-medium interface. It can use grating, prism, Different from the surface plasmon conduction mode, the surface plasmon resonance conduction mode can be strongly coupled with the external electromagnetic field. The surface plasmon conduction mode and the surface plasmon resonance conduction mode excited by metal grating structure have been widely studied. Using the finite difference time-domain method and coupled mode theory, the optical resonance characteristics of plasma mixing mode on the surface of dielectric coated metal gratings are studied in this paper. The results show that, in the studied structure, the interaction between the mixed surface mode supported by the covering medium and the surface plasma mode supported by the metal grating results in anti-cross effect, and the coupling mode theory is used. The reflection characteristics of the system are modeled and the conditions for reducing absorption are obtained. All the optical properties of the coupled system are verified by the finite-difference time-domain method, and the theoretical results are in agreement with the numerical simulation results. This study can be applied to the sensor. Coating a layer of dielectric on the metal grating can prevent it from being oxidized, which greatly improves the performance and lifetime of the sensor.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN25

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